diff -up ecryptfs-utils-87/src/pam_ecryptfs/pam_ecryptfs.c.fixexecgid ecryptfs-utils-87/src/pam_ecryptfs/pam_ecryptfs.c
--- ecryptfs-utils-87/src/pam_ecryptfs/pam_ecryptfs.c.fixexecgid	2011-07-25 16:38:48.040555555 +0200
+++ ecryptfs-utils-87/src/pam_ecryptfs/pam_ecryptfs.c	2011-07-25 16:52:22.751025667 +0200
@@ -33,6 +33,7 @@
 #include <errno.h>
 #include <syslog.h>
 #include <pwd.h>
+#include <grp.h>
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <sys/types.h>
@@ -303,6 +304,22 @@ static int private_dir(pam_handle_t *pam
 		return 1;
 	}
 	if (pid == 0) {
+		/* explicitely change group to ecryptfs if user is member of that group, changing uid is not enough */
+		gid_t *groups;
+		int grn = 0;
+		
+		getgrouplist(pwd->pw_name,pwd->pw_gid,NULL,&grn);
+		groups = malloc(sizeof(gid_t)*grn);
+		if (groups == NULL) {
+			syslog(LOG_ERR, "Error allocating memory for group list");
+			_exit(255);
+		}
+		getgrouplist(pwd->pw_name, pwd->pw_gid, groups, &grn);
+		if (setgroups(grn, groups) < 0) {
+			syslog(LOG_ERR, "Unable to set user's supplementary groups : %m");
+			_exit(255);
+		}
+
 		if (mount == 1) {
 		        if ((asprintf(&recorded,
 			    "%s/.ecryptfs/.wrapped-passphrase.recorded",